We propose to demonstrate the feasibility of an compact optically driven high power time-domain terahertz (TD-THz) source with greater than 1 milliwatt average output at a repetition rate of approximately 50 MHz. This source will be compatible with conventional time domain terahertz spectroscopy and imaging equipment, but extend the output power greater than a 1000 times the 1 microwatt typically gemerated by these systems. Time domain terahertz sources produce hyper-wideband near single cycle sub-picosecond electromagnetic impulses spanning nearly 5 octaves of spectra from less than 100 GHz to greater than 3 THz. These pulses have unique properties that simultaneously enable frequency domain applications (such as pharmaceutical spectroscopy) and time domain applications (such as reflection tomography in aerospace non-destructive examination). We propose a non-conventional optical rectification approach driven by a compact high power laser system. The approach is compatible with Picometrix's existing photoconductive receivers and time domain terahertz spectroscopy and imaging equipment. In Phase I we will demonstrate the feasibility and scaling of the high power generation approach.